Parts needed:
Lowering Springs (Obviously)
Floor Jack
Jack Stands
Chalks
Breaker Bar
Metric Wrench Set (preferably 3/8" and 1/2")
Torque Wrench
Allen Wrench Set
Hammer
Long Thin Screwdriver
Pliers
Spring Compressors (Possibly)

Start by applying the emergency brake and chalking the rear wheels up with chalks or bricks or whatever you have handy.  At this point you may want to measure the height of your vehicle in the front and the back so that you can determine how far it was lowered by the springs.
Front:

Rear


Loosen the lug nuts on the front wheels and then use your floor jack to jack the front of the van up in the center.  Place your jacks stand on either side of the van and lower the van onto the jack stands. Remove the lug nuts and wheels from the front of the van.  Now it's time to get into the real work.

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